Electric pneumatic clamp holder

Abstract

A gripper for an industrial manipulator, in particular for an apparatus for visual inspection of transparent or translucent containers, is described. The gripper includes a main body having an electric motor housed therein and a rotatable portion constrained to the main body. In order to hold and release the workpiece, clamping jaws are provided on the rotatable portion that can be moved close to and away from each other. The electric motor is used to impart rotation to the rotatable portion when the workpiece is clamped between the clamping jaws. The gripper also includes a pneumatic actuator, such as a piston, for controlling the opening of the jaws to release the workpiece. When the electric actuator is open, the electric actuator and the pneumatic actuator remain separate and do not interact. And vice versa, when the pneumatic actuator works, the electric actuator and the pneumatic actuator are integral. The gripper is particularly suitable for use in a carousel-type inspection system for inspecting the quality of containers and vials in the pharmaceutical industry.

Description

Technical Field

[0001] The present invention relates to an electro-pneumatic gripper for an industrial manipulator, and in particular to an electro-pneumatic gripper for an apparatus for inspecting containers and vials in the pharmaceutical industry. Technical Background

[0002] Grippers in combination with manipulators to grip, move and release objects are well known in the field of industrial automation.

[0003] Grippers for industrial manipulators are generally provided with a body and two or more jaws or gripper fingers mounted on the body. The jaws can be moved away from or towards each other between an open or release position, in which they do not exert any pressure on the item to be manipulated, and a closed or gripping position, in which they exert sufficient pressure on the item to be manipulated to ensure that the workpiece is not accidentally released during its handling.

[0004] The jaw movement is achieved by using an electric actuator, such as an electric motor housed in the gripper body, or a pneumatic actuator, such as a cylinder-piston system also housed in the gripper body and supplied with compressed air.

[0005] A specific case involves grippers of inspection devices for performing quality control of containers and vials in the pharmaceutical industry. These inspection devices are optical inspection devices used to inspect transparent or translucent vials, bottles, containers positioned along a production line in order to perform a 100% quality control of the produced containers in terms of the integrity of the containers and the corresponding closures, as well as in terms of the quantity and purity of the contents. In this inspection device, a plurality of grippers are arranged in a line or, depending on the configuration of a turntable, in a circle, with the grippers adjacent to each other. Each gripper picks up a container to bring it in front of a camera that captures one or more images of the container itself; the images are processed by a computer to detect any anomalies. A flash is usually used to capture the images.

[0006] In this type of inspection device, the gripper is usually arranged on a turntable structure and, in addition to the conventional opening and closing movement of the gripper, the gripper is also required to rotate on its own longitudinal axis (which also corresponds to the axis along which the workpiece is gripped) in order to simultaneously generate eddies in the liquid contained in the container / vial to be inspected. The images of the container and of the eddies acquired by the inspection device allow the identification of anomalies, such as the presence of impurities in the liquid, or excesses or deficiencies in the amount of liquid, liquid viscosity, etc.

[0007] Since the grippers are located next to each other and the space available on the turntable is extremely small, grippers without their own actuators are preferred in the inspection apparatus just described, precisely because the actuators would have a negative impact on the overall dimensions of each gripper and, ultimately, on the number of grippers that can be mounted on the turntable. In practice, if the grippers were equipped with their own actuators for rotating the jaws and opening / closing the jaws, the grippers would have larger overall dimensions than those available today and, other things being equal, the same turntable would inevitably be equipped with fewer grippers.

[0008] In the most common solution, the gripper mounted on the inspection device comprises a rod mounted slidingly in a specific seat in the body of the gripper; the rod is movable on the longitudinal axis between a distal position and a proximal position in response to a force exerted by a cam controlled by other mechanisms of the inspection device. In particular, all grippers have a cam. The position of the rod relative to the body of the gripper unambiguously determines the position of the jaws, i.e. mechanically controls their opening and closing. In other words, the gripping and release of the container are controlled by a cam external to the gripper, in particular the cam of the inspection device, but which acts on a sliding rod of each gripper; a suitable spring or other reversing means brings the rod back to the initial closed position of the jaws.

[0009] In other known solutions, which also provide for rotating the jaws and thus the container or vial, the rotation of the gripper on the longitudinal axis is achieved by mounting the gripper on a turntable structure of the inspection device and by prearranging an electric motor on the turntable structure for rotating the rotatable part of the gripper including the jaws. The electric motors are each connected to one or more grippers by a drive belt. The rotation of the pulleys of the electric motors is transmitted by the belt to the rotatable parts of the corresponding grippers, thereby rotating them on the corresponding longitudinal axis. The rotation speed is usually between 400 and 800 revolutions per minute, but can also reach 3000 revolutions per minute.

[0010] In these conventional solutions, the grippers can therefore be defined as passive grippers, since they do not have their own actuators inserted into the body of the gripper for opening / closing the jaws and for their corresponding rotation, and their operation depends on cams and electric motors of the inspection device, which are on a turntable structure.

[0011] Grippers equipped with their own actuator, ie an actuator mounted on the gripper, for rotating the gripper jaws have also recently been proposed.

[0012] IT202019000002871, filed on August 27, 2019 in the name of the applicant, describes a gripper for an industrial manipulator, in particular a gripper for an apparatus for visual inspection of transparent or translucent containers, comprising:

[0013] - a body provided with a longitudinal axis and capable of being fastened to an inspection device,

[0014] - a rotatable part constrained to the body and rotatable relative to the body on the longitudinal axis,

[0015] - an electric motor housed in the body of the holder for rotating the rotatable part on the longitudinal axis, and

[0016] - gripping jaws mounted on the rotatable part and movable towards and away from each other relative to the rotatable part in order to pick up and release the container or vial, i.e. movable to open and close;

[0017] - drive means for controlling the opening and closing movement of the jaws in response to stresses applied by an actuator of the inspection apparatus, ie an actuator external to the gripper.

[0018] In more detail, the clamp comprises a hollow drive shaft arranged on the longitudinal axis of the clamp. The hollow drive shaft is connected to the rotatable part of the clamp so that the rotation relative to the longitudinal axis applied to the drive shaft by the electric motor is transmitted to the jaws. Therefore, the longitudinal axis of the clamp is also the axis of rotation of the jaws. The control rod of the jaws is telescopically (i.e. slidingly) accommodated in the drive shaft and has precisely the function of opening the jaws. The displacement of the control rod relative to the drive shaft is applied by an external actuator, for example, a cam of an inspection device on which the clamp is mounted. When the stress applied by the cam on the control rod ceases, the elastic element automatically returns the jaws to closure.

[0019] IT102009901732640, filed on May 15, 2009 in the name of Pharmamech, describes a gripper per se, provided with an actuator that imparts the rotation of the jaws and controls their opening. In particular, the document describes two embodiments of a gripper designed to manipulate test tubes or vials in an inspection device for quality control. With reference to the corresponding figures, both embodiments are provided with an actuator coaxial with respect to the axis of the gripper that controls the rotation of the jaws and their respective opening and closing. In particular, the actuator controls an outer shaft 8 and a control rod 10 arranged coaxially. The outer shaft 8 is hollow, and the control rod 10 is inserted therein so as to slide telescopically. In a first embodiment, the outer shaft 8 is a drive shaft rotated by the actuator when the gripper is closed, so as to rotate the test tube or vial and allow inspection with an optical system. When the gripper is stationary, the control rod 10 is actuated, i.e. it is translated relative to the drive shaft 8, in order to open the jaws and release the tube / vial. In a second embodiment, the actuator is called a "rotational actuator device" 14 and acts only on the control rod 10, which is easy to translate relative to the drive shaft 8 to open and close the gripper, and easy to rotate to rotate the tube / vial, while the drive shaft 8 remains idle.

[0020] CN1111353 describes a clamp in which opening and closing are controlled by an axial rod, which is however controlled by a misaligned actuator and the rotation is imparted by a pulley system.

[0021] US 2008 / 0085507 describes a rotary gripper with three jaws: the opening and closing of the jaws are controlled by the same axial motor that controls the gripper rotation, but the movement of the jaws is achieved by rotating the jaws on an axis parallel to the gripper axis by means of spur gears.

[0022] US2009 / 0179445 describes a gripper equipped with two motors, a first rotary motor applying rotation to a hollow drive shaft indicated by 20 in the figure in order to rotate the jaws, and a second linear motor indicated by 22 in the figure and housed in the drive shaft 20, acting as a telescopic push rod to open and close the jaws.

[0023] WO2023 / 084350 in the name of the applicant describes a gripper comprising a body provided with a longitudinal axis, a rotatable part constrained to the body so as to be able to rotate on the longitudinal axis, an electric motor for applying rotation to the rotatable part, and a clamping jaw mounted on the rotatable part and movable towards and away from each other to pick up and release an object. The electric motor is a single motor housed in the body of the gripper. Specifically, the electric motor applies rotation to a drive shaft that is coaxial with the longitudinal axis and connected to the upper part so that the clamping jaw can rotate on the longitudinal axis of the gripper. The assembly formed by the electric motor and the drive shaft is susceptible to translation along the longitudinal axis in response to a driving force applied by an actuator outside the gripper (in particular an actuator of an inspection device on which the gripper is mounted) so as to apply a movement closer to / away from each other to the clamping jaws, and thus determine the opening and closing of the clamping jaws. Summary of the invention

[0024] The object of the present invention is to provide an electric gripper, i.e. one equipped with its own electric motor for exerting rotation of the gripping jaws and of the manipulated part, which gripper is at the same time simple to make, compact and suitable for controlling the opening and closing of the gripping jaws without requiring the intervention of specific actuators external to the gripper, in particular without requiring the intervention of cams or drive belts of the inspection device on which the gripper is mounted.

[0025] In other words, the present invention aims at providing a clamp which is itself provided with the means required for imparting rotation to the jaws and controlling the opening and closing movements of the jaws, which is in any case interchangeable with the known clamps and which therefore has overall dimensions not greater than those of the known clamps, so as to be able to retrofit and replace them without having to modify the inspection equipment with which the clamp is combined.

[0026] The present invention therefore relates to a gripper for an industrial manipulator according to claim 1 .

[0027] In particular, the present invention relates to a holder comprising:

[0028] - a body having a longitudinal axis and intended to be fastened to an external device, such as an inspection device for inspecting vials and containers, in particular a turntable structure,

[0029] - a first electric actuator housed in the body so as to remain within the overall dimensions of the body of the clamp,

[0030] - a rotatable part constrained to the body and rotatable relative to the body on the longitudinal axis,

[0031] - jaws mounted on the rotatable part and movable towards and away from each other in order to open / close the gripper and thereby hold and release the workpiece.

[0032] The gripper also includes a control shaft that engages the jaws and controls their movement toward and away from each other. The control shaft is coupled to the electric actuator, thereby forming:

[0033] - rotation about the longitudinal axis by means of an electric actuator in order to rotate the rotatable part and the jaws present on the rotatable part, and

[0034] - can be translated on the longitudinal axis in order to move the jaws towards each other or away from each other and thus for opening and closing the gripper.

[0035] The rotation of the rotatable part together with the workpiece held by the gripper is caused by rotating the control shaft. The opening of the gripper jaws and the release of the workpiece or the preparation of the gripper for picking up a new workpiece is caused by translating the control shaft.

[0036] The gripper includes a second pneumatic actuator also housed in the body. The pneumatic actuator includes a piston movable in a cylinder between a bottom dead center pmi and a top dead center pms in response to pressure exerted by compressed air supplied to the gripper by an external device, such as a pneumatic line of an inspection apparatus.

[0037] The piston is configured to interact with the control shaft so as to functionally constrain itself to the control shaft during at least a portion of the piston's travel. The functional constraint consists in the ability of the piston to exert a thrust on the control shaft so as to translate it on its longitudinal axis.

[0038] In this way, the movement of the piston between the bottom dead center pmi and the top dead center pms causes the control shaft to translate on the longitudinal axis and actuates the opening of the clamping jaws if the clamp is normally closed, or the closing of the clamping jaws if the clamp is normally open.

[0039] The two actuators (electric and pneumatic) remain separated and do not interact when the electric motor is on (i.e. when the jaws remain in rotation). Vice versa, the electric and pneumatic actuators are integral, at least in translation, while the pneumatic actuator is active, i.e. when it is supplied with compressed air to open the jaws. These two states are asynchronous and alternate with each other: when the jaws rotate on the longitudinal axis, they cannot open to release the workpiece.

[0040] The solution just described has various advantages over known clamps.

[0041] A first advantage consists of the complete interchangeability of the gripper with respect to grippers of known art used in inspection devices for inspecting containers and vials, since the gripper according to the invention can be made with a body having the same external diameter dimensions as the body of the known gripper;

[0042] A second advantage is that the gripper is provided with two actuators, one electric and the other pneumatic, replacing the actuators usually provided in the inspection device or machine on which the gripper is mounted. The two actuators allow the movements required to pick up / release the workpiece and to rotate the workpiece to be applied to the jaws by means of actuators independently of the device on which the gripper is mounted. This circumstance in turn allows the manufacture of the simplest inspection devices and machines, without the possibility of belts or other parts being subject to wear and releasing particles into the air.

[0043] A third advantage is the use of two actuators, one electric and the other pneumatic, and allows the gripper to have a simpler mechanical structure than a solution with a single rotary-translational actuator.

[0044] The structure of the holder is relatively simple, since it does not provide concentric axes as provided by solutions of the known art, thus making it possible to assemble it in a short time and without excessive costs.

[0045] In a preferred embodiment, the electric actuator is an electric motor, for example having a cylindrical body and having a drive shaft extending on a longitudinal axis and rotatable on the same axis. The drive shaft of the electric motor rotates integrally with the control shaft, in the sense that the two shafts are coupled to rotate integrally (synchronously). As an alternative, the control shaft and the drive shaft can be the same component, i.e. the control shaft can be part of the drive shaft. However, a preferred solution is more practical in which the shafts are made separate and continuously connected.

[0046] For example, the control shaft and the drive shaft are non-telescopically and non-concentrically coupled, so that the control shaft constitutes an extension of the drive shaft on the longitudinal axis. The connection can be achieved by threaded connection, or by mechanical interference, etc.

[0047] In a preferred embodiment, the electric motor is slidably housed in the body of the gripper, which, in response to the stress applied by the pneumatic actuator, is easily translated along the longitudinal axis from the bottom dead center pmi to the top dead center pms. In other words, the electric motor floats in the body of the gripper. The bottom dead center pmi of the electric motor corresponds to a reciprocating position of the jaws selected from the closed position and the spaced position, and the top dead center pms of the electric motor corresponds to another reciprocating position of the jaws selected from the closed position and the spaced position, depending on whether the gripper is configured as normally open or normally closed.

[0048] An axial displacement of the electric motor produces a corresponding axial displacement of the control shaft.

[0049] The elastic element is functionally interposed between the body and the electric motor so as to counteract the translation of the electric motor on the longitudinal axis and, when the thrust exerted by the pneumatic actuator ceases, bring the electric motor back to the initial axial position, or in any case to a retracted position, also different from the initial position and corresponding to the jaws pressing against the workpiece: this retracted position will depend on the overall dimensions of the workpiece and therefore on the distance between the jaws holding the workpiece.

[0050] The gripper is preferably configured to be normally closed. The elastic element is a spring housed in the body, which is located between the rotatable part and the electric motor. The spring is preloaded so that a thrust is constantly exerted on the electric motor in the direction of bringing the electric motor to the corresponding bottom dead center PMI, which corresponds to the jaws closing together and closing onto the workpiece to be manipulated.

[0051] The spring is preferably coaxial with the longitudinal axis, and more preferably surrounds the control shaft.

[0052] In a preferred embodiment, the clamp comprises a sleeve constrained to the electric motor and concentric with the drive shaft and the control shaft, and an elastic element. For example, a spring is housed in the sleeve and the control shaft is inside the spring. When the electric motor is at the corresponding top dead center, the sleeve contacts the end of the body of the clamp, thereby determining the limit stop. In other words, when the electric motor is pushed to the top dead center, the sleeve is integrated with the electric motor and operates like a spacer relative to the end of the body of the clamp.

[0053] The holder comprises a plurality of radial pins which are inserted through corresponding through holes which are also radial and which are bored through the side wall of the body of the holder to prevent the sleeve from rotating on the longitudinal axis. For each radial pin, the sleeve comprises a slot which is elongated in the axial direction. The radial pins engage the corresponding through holes by intervention and each radial pin is at least partially inserted into the corresponding elongated slot. In other words, the radial pins simultaneously engage the slots in the body of the holder and in the sleeve, which prevents the sleeve from rotating (anti-rotation function). The axial limit stop of the sleeve corresponds to the radial pin, which abuts against one of the two ends of the corresponding elongated slot; in other words, the radial pin prevents the sleeve from rotating but allows the sleeve to move axially together with the motor, the stroke of the axial movement corresponding to the range of the slot in the axial direction.

[0054] The jaws are slidably received in corresponding guides, such as radial guides, of the rotatable part. The jaws may be two or more than two, such as three.

[0055] In a preferred embodiment, the jaws are two, which slide in the same guide orthogonal to the longitudinal axis. The gripper comprises a lever for each jaw, which pivots relative to the rotatable part and oscillates in a plane parallel to the longitudinal axis. The oscillation of the lever is controlled by a control shaft: the end of the control shaft is slidably inserted in the rotatable part and engages the lever, so that the angular position of each lever corresponds univocally to the axial position of the control shaft. For example, the end of the control shaft can be provided with a chamfer, into which the lever is inserted; alternatively, the end of the shaft can be hinged to the lever or engaged to the lever.

[0056] The transmission of rotation from the control shaft to the rotatable part can be achieved in two ways:

[0057] - In a first mode, the holder comprises a pin inserted radially through the control shaft. The pin engages a slot of the rotatable part so as to transmit rotation about the longitudinal axis and the pin slides axially in the slot. The axial extent of the slot is equal to or greater than the axial travel of the control shaft;

[0058] In a second way, at least a portion of the control shaft engaging the rotatable part has a non-circular cross section, such as a polygonal cross section, and engages with a corresponding non-circular guide, such as a complementary guide, of the rotatable part.

[0059] In both cases, the rotation applied to the control shaft by the electric motor is transmitted to the rotatable part which will rotate on the longitudinal axis relative to the body of the gripper and the control shaft will anyway slide inside the rotatable part in order to actuate the jaws.

[0060] In a preferred embodiment, one end of the control shaft projects from the body of the gripper and engages with the rotatable portion. The control shaft is telescopically movable relative to the gripper body between a retracted position and an extended position, the retracted position and the extended position corresponding to a state selected from the jaws closed together and the jaws spaced apart, respectively, depending on whether the gripper is normally closed (preferred state) or normally open (motion reversed).

[0061] In the case of a pneumatic actuator, the piston comprises a thrust portion or rod. At the bottom dead center pmi of the piston, the rod is separated from the electric actuator, i.e. it does not contact the electric actuator and does not exert a thrust on it. At the top dead center pms of the piston, the rod abuts against the electric actuator and exerts an axial thrust on it, which causes the electric actuator to translate within the body of the gripper, which in turn causes the control shaft to extend and actuate the jaws.

[0062] In a preferred embodiment, as described above, the electric actuator is an electric motor with a drive shaft rotatable on a longitudinal axis. The drive shaft passes through the electric motor, i.e. one end of the drive shaft protrudes toward the control shaft and the opposite end of the drive shaft protrudes toward the pneumatic piston, in particular toward the rod of the piston. When the pneumatic piston is pushed by compressed air, the rod of the piston can abut against the corresponding end of the drive shaft. In this case, the electric motor is turned off and the drive shaft does not rotate.

[0063] In particular, at the bottom dead center of the pneumatic piston, the rod is separated from the drive shaft, not in contact with the drive shaft and rotationally separated from it. Thus, in this configuration, the rotation applied to the drive shaft by the electric motor cannot be transmitted to the rod of the pneumatic piston; therefore, the pneumatic piston does not rotate on the longitudinal axis. In this case, the electric motor can be turned on and the drive shaft rotated.

[0064] Preferably, an elastic element is functionally interposed between the electric actuator and the pneumatic piston to offset the axial displacement of the pneumatic piston. The elastic element is preloaded and constantly exerts a thrust on the piston in a direction that moves the piston away from the electric actuator so as to return the piston to the bottom dead center pmi when the compressed air supply stops.

[0065] In a preferred embodiment, the operation of the gripper is as follows. The jaws are normally closed, and they need to be opened to allow the insertion of the workpiece to be picked up between them; the removal of the jaws is achieved by supplying compressed air to the pneumatic actuator, with the electric motor turned off and the drive shaft therefore not rotating. The compressed air pushes the pneumatic piston to the top dead center, which determines the axial displacement of the kinematic chain consisting of the electric actuator, the control shaft, the joystick and finally the jaws. Once the workpiece is inserted between the jaws, the supply of compressed air is interrupted and the elastic element moves the kinematic chain just described backward; the pneumatic piston returns to its bottom dead center, while the electric actuator and the control shaft do not return to the initial point, because the jaws are closed to the workpiece and the overall size of the workpiece determines the return stroke of the electric actuator and the control shaft. The thrust exerted by the elastic element around the control shaft keeps the jaws pressed against the workpiece so as to hold the workpiece. At this point, the electric motor can be operated to rotate the drive shaft and the control shaft, thereby causing the rotation of the rotatable part of the gripper and the workpiece clamped between the jaws. At the end of the operation, the electric motor is turned off to stop the rotation and the workpiece can be released by supplying compressed air to the pneumatic actuator and causing the jaws to open, as described above. In view of the above, the rotation of the drive shaft and the control shaft and the translation of these two axes are asynchronous, that is, they do not occur simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Further characteristics and advantages of the present invention will become more apparent on review of the following detailed description of a preferred but not exclusive embodiment of the invention illustrated by way of example and not by way of limitation with the aid of the accompanying drawings, in which:

[0067] Figure 1 is a perspective elevational view of an inspection device for inspecting vials, the inspection device comprising a gripper according to known technology and a gripper according to the invention;

[0068] Figure 2 is an exploded view of a holder according to the present invention;

[0069] Figure 3 yes Figure 2 A perspective view of the holder shown in ;

[0070] Figure 4 yes Figure 2 An axial cross-sectional view of the clamp shown in , with the jaws close together or closed;

[0071] Figure 5 yes Figure 2 An axial cross-sectional view of the clamp shown in , with the jaws spaced apart or open;

[0072] Figure 6 yes Figure 2 A perspective view of the gripper and the container to be picked up shown in , with the jaws close together or closed;

[0073] Fig. 7A yes Figure 2 The holder is shown in Figure 4 and Figure 6 an axial cross-sectional view of the configuration shown, wherein the jaws are close together or closed;

[0074] Figure 7B yes Fig. 7A an enlarged view of the portion enclosed by the dotted rectangle;

[0075] Figure 8 yes Figure 2 A perspective view of a gripper and a container to be picked up, with the jaws spaced apart or open and the container inserted between the jaws;

[0076] Fig. 9A yes Figure 2 The holder is shown in Figure 5 and Figure 8 an axial cross-sectional view of the configuration shown, wherein the jaws are spaced apart or open;

[0077] Fig. 9B yes Fig. 9A An enlarged view of the portion enclosed by the dashed rectangle;

[0078] Fig.10 yes Figure 2 A perspective view of the gripper shown in , with the gripper jaws closed onto a container to be picked up and rotated;

[0079] Fig.11A yes Figure 2 The holder is shown in Fig.10 an axial cross-sectional view of the illustrated configuration with the holder closed onto the container;

[0080] Fig. 11B yes Fig.11A an enlarged view of the portion enclosed by the dotted rectangle;

[0081] Fig. 12A is a perspective view of a gripper hand of a manipulator in a first configuration, the manipulator being equipped with different embodiments of grippers according to known technology, intended for tightening and loosening container closures;

[0082] Fig. 12B yes Fig. 12A An enlarged view of the portion included in the dashed box;

[0083] Fig.13A It is in the second configuration Fig. 12A A perspective view of the gripping hand shown in ;

[0084] Fig. 13B yes Fig.13A An enlarged view of the portion included in the dashed box. DETAILED DESCRIPTION

[0085] In the drawings, the terms top, upper, bottom, lower should be understood to refer to the orientation the holder has in the drawing itself.

[0086] Figure 1 A turntable structure 500 of an inspection device for inspecting vials or containers V (hereinafter simply referred to as containers V) is shown in perspective view. The turntable structure 500 includes a circular frame 501 that is intended to rotate to bring the container V in front of an optical image capture and processing system to inspect the quality of the container V and its corresponding content.

[0087] A holder 502 according to known technology and two holders 1 according to the invention are mounted at regular intervals on the edge of a circular frame 501: Figure 1 It thus allows to contextualize the use of the grippers 502, 1 and to compare them.Each gripper 1, 502 holds a container V while the circular frame 501 rotates on its own axis.

[0088] As far as the grippers 502 according to the prior art are concerned, each gripper 502 comprises a body 503 fastened to a circular frame 501 and a part 504 rotatably constrained to the body 503, without the possibility of relative movement of the body 503. Electric motors 505, in particular one motor 505 for every two grippers 502, are fastened to the circular frame. Each electric motor 505 is connected to two grippers 502 by a toothed belt 506 and a toothed wheel 507, which together define a drive system. The toothed wheel 507 can rotate relative to the body 503 of the corresponding gripper 502 on the longitudinal axis of the gripper 502: the rotation of the toothed wheel 507 applied by the electric motor 505 by means of the toothed belt 506 causes the rotation of the rotatable part 504 relative to the body 503 of the gripper 502 and the rotation of the container V together with the rotatable part 504. The opening and closing of the jaws 508 of the gripper 502 is controlled by an actuator ( Figure 1 (not visible in the image) control.

[0089] As far as the holder 1 according to the present invention is concerned, as can be seen by observing Figure 1 It can be noted that they are not combined with the electric motor 505 of the inspection device. The gripper 1 is connected to a compressed air source by a corresponding connection line 509 and to a power supply by an electric line 510. It is important to note that the gripper 1 according to the invention is completely interchangeable with the gripper 502 according to the known technology and can therefore be used to retrofit existing inspection devices, thereby simplifying the fine setting of the turntable structure. In fact, by only equipping the circular frame 501 with the gripper 1 instead of the gripper 502, it is no longer necessary to install the electric motor 505, the toothed belt 506 and the gear 507. This brings about a significant structural simplification, a small overall size of the area above the circular frame 501 and a small weight contained in the turntable structure, as well as greater cleanliness, because it is no longer necessary to use a rubber belt on the turntable structure, which is well known to be subject to wear and tear, which causes the formation of rubber particles that contaminate the structure and the container. The weight reduction of the circular frame 501 in turn brings about a corresponding reduction in the inertia of the system during acceleration and braking, and therefore contributes to a higher productivity of the inspection device under the same conditions of all other factors, thereby being able to perform the inspection of more batches of containers V per unit time.

[0090] Figure 2 is an exploded view of a gripper 1 for an industrial manipulator according to the invention, the gripper 1 being particularly suitable for being mounted on an inspection device for inspecting transparent or translucent containers V, for example in the pharmaceutical industry.

[0091] Figure 3 is a perspective view of the assembled holder 1 .

[0092] refer to Figure 2 and Figure 3 The holder 1 includes a device that can be fastened to an external structure (e.g. Figure 1 The main body 2 is provided with a longitudinal axis XX of the holder 1. In the embodiment shown in the figures, the main body 2 is cylindrical and hollow to accommodate certain components of the holder 1.

[0093] The holder 1 also comprises an end portion 3 cantilevered from one end of the body 2, thus being rotationally constrained to the body 2 and not free to rotate on the longitudinal axis XX, but under conditions to be described below.

[0094] Typically, the gripper 1 may comprise a plurality of jaws, for example three or four; in the embodiment 1 shown in the figures, the jaws are two and are identified by reference numerals 4 and 5. The jaws 4 and 5 slide in a guide 6 of the rotatable part 3, the guide 6 extending perpendicularly to the longitudinal axis XX, i.e. radially. The jaws 4 and 5 are therefore easily displaced in the guide 6, so as to move closer to close the gripper 1 and clamp the container V, and to move apart to open the gripper 1 and release the container V. This configuration is not the only possible one: the gripper 1 can in fact also be made as jaws 4 and 5 which pivot relative to the rotatable part 4 and can rotate relative to the rotatable part 4 without sliding in the guide.

[0095] In more detail, the jaws 4 and 5 are radially movable between a proximal position relative to the longitudinal axis XX, corresponding to a gripping position of a container V or a common workpiece, and a distal position relative to the longitudinal axis XX, corresponding to a release position of the container V or the workpiece.

[0096] The thrust for moving the jaws 4 and 5 in the guide 6 is exerted by the respective levers 4' and 5', which are pivoted to the rotatable part 3 by means of pins 7 and 8. The pins 7 and 8 are mounted offset relative to the longitudinal axis XX, or in other words, the levers 4' and 5' oscillate in a plane parallel to the longitudinal axis XX, and in particular in the example shown in the figures, in a plane containing the longitudinal axis XX.

[0097] A bearing 9 of the ball or roller type is housed in a corresponding seat 9' in the body 2 of the holder 1; the function of the bearing 9 is to allow the rotatable part 3 to rotate on the longitudinal axis XX relative to the body 2. A washer or annular nut for retaining the bearing 9 in the seat 9' is indicated by the reference numeral 9"; the washer 9" fits into a corresponding cross-sectional narrowing of the control shaft 10 (barely visible in the figure).

[0098] The gripper 1 also comprises a control shaft 10 coaxially and telescopically housed in the body 2. The function of the control shaft 10 is dual and asynchronous: alternately rotating the rotatable part 3 and controlling the opening and closing of the jaws 4, 5. In particular, the control shaft 10 is coaxial with the body 2, in the sense that it extends along a longitudinal axis XX and is susceptible to rotation clockwise and / or counterclockwise on the same axis XX in response to the thrust exerted by the electric motor, as will be described below. The control shaft 10 is almost completely housed in the body 2, except for an end 10' that protrudes from the body 2 and is inserted in the rotatable part 3 through an opening 3', which also serves as a guide for the end 10'. On the end 10' of the control shaft 10 there are two diametrically opposed grooves 11, each of which engages with a corresponding operating lever 4' or 5'.

[0099] The control shaft 10 is also susceptible of being moved alternately in translation on the longitudinal axis XX between a retracted position and an extended position, as will be explained below.

[0100] The axial displacement of the control shaft 10 toward the extended position causes the end 10' to move away from the body 2, thereby causing the jaws 4 and 5 to separate and the clamp 1 to open; vice versa, the axial displacement of the control shaft 10 toward the retracted position causes the end 10' to move closer to the body 2 and the jaws 4 and 5 to close, i.e., the clamp 1 is closed.

[0101] In fact, as can be noted, the levers 4 ′ and 5 ′ each comprise two leaf-like portions 12 and 13 , one leaf-like portion 12 intended to engage the respective jaw 4 , 5 , the other leaf-like portion 13 intended to engage the respective groove 11 present on the control shaft 10 .

[0102] In order to prevent the rotatable part 3 from being separated from the main body 2 of the clamp 1 and to maintain the connection with the control shaft 10, the clamp 1 is provided with a stop pin 14, which is radially inserted into the corresponding groove 15 of the rotatable part 3 and inserted into the corresponding radial hole 16 of the control shaft 10. This is for the purpose of retaining the rotatable part 3 on the control shaft 10.

[0103] As can be noted by observing the attached figures, the slot 15 is elongated in the axial direction; the reason for this configuration is that, as mentioned above, although the control shaft 10 is susceptible to axial translation and therefore telescopes relative to the body 2, the axial position of the rotatable part 3 relative to the body 2 does not change. Therefore, the slot 15 allows the stop pin 14 to move therein so as to support the translation of the control shaft 10 between the retracted position and the extended position, but without transmitting undesirable stresses to the rotatable part 3. On the other hand, the pin 14 transmits the rotation, in a sense that the pin 14 is precisely the pin that allows the rotation applied to the control shaft 10 on the longitudinal axis XX to be transmitted to the rotatable part 3.

[0104] In an embodiment not shown in the figures, as an alternative to using a pin 14 to constrain the control shaft 10 to the rotatable part 3 and to make the two elements rotate as one on the longitudinal axis XX, the control shaft 10 is made with an end 10' having a polygonal section, for example square, hexagonal, etc.; the opening 3' of the rotatable part 3 guiding the end 10' of the control shaft 10 has a section complementary to that of the end 10'. Thanks to this detail, when the control shaft 10 rotates on the longitudinal axis XX, it drives the rotatable part 3 in rotation without using a pin 14, simply due to the shape coupling between the elements 10' and 3'. This detail does not affect the axial movement of the control shaft 10 relative to the rotatable part 3. The anti-bending function is thus achieved in an alternative way to the one described above.

[0105] The axial movement of the control shaft 10 is counteracted by an elastic element, which in the example shown is a spring 17 coaxially mounted on the control shaft 10. The clamp 1 is preferably configured so that the closed position of the jaws 4 and 5 is the normal position, i.e. the clamp is normally closed, and the opening (i.e. spacing) of the jaws 4 and 5 occurs only in response to an axial movement of the control shaft 10 towards the extended position. Therefore, the spring 17 is inserted into the body 2 with a preload and is functionally interposed between the end of the body 2 and the control shaft 10 to constantly exert a force on the control shaft 10, which keeps the control shaft 10 in the retracted position or returns the control shaft 10 to the retracted position.

[0106] Making the gripper 1 normally closed is a conservative choice in terms of safety, since it ensures that the jaws 4 and 5 maintain their grip on the container V, also in the absence of pneumatic power to the gripper 1. Obviously, it is also possible to have the gripper in the opposite configuration, i.e. normally open, activated to close the gripper, but this option would result in lower safety and greater energy consumption.

[0107] Inside the body 2, a sleeve 18 is also housed coaxially with the body 2, the control shaft 10 and the spring 17, respectively, in a radially outer position relative to the control shaft 10 and the spring 17. The sleeve 18 slides axially in the body 2 of the holder 1 between the lower and upper dead centers for a length corresponding at least to the travel of the control shaft 10 between the retracted position and the extended position; the inside surface of the body 2 serves as a cylinder into which the sleeve 18 slides. To prevent the sleeve 18 from rotating on the longitudinal axis XX, the same sleeve 18 is locked in rotation by pins 19 (three in the example shown and arranged at 120°). The pins 19 are inserted in radial holes 20 drilled on the side wall of the body 2 of the holder 1 and extend in length until each pin engages a corresponding groove 21 formed on the side wall of the sleeve 18. The grooves 21 extend axially to allow the axial translation of the sleeve 18, as described above.

[0108] Inside the body 2, below the control shaft 10 when observing the figures, there is a single electric motor M, whose drive shaft 22 is coaxial with the longitudinal axis XX and is fastened to the control shaft 10, for example by a threaded butt coupling, so that the drive shaft 22 and the control shaft 10 are integral in rotation and translation. The outer diameter of the electric motor M is slightly smaller than the inner diameter of the body 2 of the gripper 1, so that the axial displacement of the motor M is not hindered by contact with the body 2. The stroke of the electric motor M in the body 2 is between 5 mm and 15 mm, preferably 8 mm. The electric motor M thus floats in the body 2.

[0109] The sleeve 18 acts as an upper seat for the motor M, which can be axially translated inside the body 2. When the sleeve 18 reaches the upper dead center, which corresponds to the sleeve abutting against the end of the body 2 on which the rotatable part 3 is located, the motor M reaches an extreme stop and can no longer move forwards. In this sense, the sleeve 18 acts as a spacer, preventing excessive compression of the spring 17 and excessive thrust on the bearing 9 and the control shaft 10 overcoming the limit stop in the extended position.

[0110] The upper end of the electric motor M, from which the drive shaft 22 protrudes, is held at its edge against the sleeve 18 , and against the lower end of the control shaft 10 .

[0111] The drive shaft 22 passes through the electric motor M from one side to the other side, that is, it is a through shaft. In particular, the lower end of the drive shaft 22 is kept flush with the lower surface of the electric motor M.

[0112] The electric motor M, preferably of the brushless type, consists of Figure 1 Activation of the electric motor M determines the clockwise or counterclockwise rotation of the drive shaft 22, which in turn rotates the control shaft 10 and the rotatable part 3 with the jaws 4 and 5. Thus, the first kinematic chain comprises the assembly of elements M, 22, 10, 3, 5, 4', 5', and activation of the electric motor M determines the rotation of the jaws and thus of the container V that may be held on the longitudinal axis XX.

[0113] The body 2 of the holder 1 is closed at the bottom by a cap 23 provided with an axial through hole 24 .

[0114] The gripper 1 also comprises means for controlling the opening of the jaws 4, 5, as will now be described, and in particular comprises a pneumatic actuator 25 for this function.

[0115] The pneumatic actuator 25 comprises a piston 26 equipped with a rod 27 and a corresponding cylinder 28, which in the example shown is a cylindrical element that can be screwed to the body 2 of the gripper 1 at the lower part of the body 2 of the gripper 1. The rod 27 of the piston 26 is slidably inserted through the axial through hole 24 passing through the cap 23. The cylinder 28 is Figure 1 The piston 26 is axially inserted into the cylinder 28, so that it can respond to the compressed air supplied by the piston 26. Figure 1 The piston 26 is moved alternately along the longitudinal axis in both directions by the thrust exerted from time to time by compressed air supplied by the connection line 509 shown in FIG. The rod 27 of the piston 26 faces the electric motor M. A gasket 29 of the single lip or O-ring type surrounds the piston 26 and ensures sealing with the cylinder 28.

[0116] In the example shown in the figures, the volume (or space) in which the piston 26 moves is therefore delimited below and laterally by the cylinder 28 and at the top by the cover 23 .

[0117] The cylinder 28 is considered to be part of the body 2 when it is screwed or fastened in any way to the rest of the body 2 .

[0118] A spring 30 is present between the piston 26 and the electric motor M, and in particular between the rod 27 of the piston 26 and the drive shaft 22 of the electric motor M, and is arranged coaxially with these elements. The rod 27 of the piston 26 and the drive shaft 22 of the electric motor M are not integral, in the sense that they are not fastened to each other, but as will be explained below, axial movement between these elements is possible.

[0119] Figure 4is an axial section of the gripper 1, in particular of a section considered on a plane containing the longitudinal axis XX and the middle axis relative to the jaws 4, 5. The gripper 1 is shown in a closed state, i.e. the jaws 4, 5 are closed together. In this configuration, the piston 26 is at the corresponding lower dead center pmi in the cylinder 28, which is not supplied with compressed air. The rod 27 of the piston 26 is separated from the drive shaft 22 of the electric motor M, so that a possible rotation applied to the drive shaft 22 by the electric motor M is not transmitted to the piston 26, but only to the rotatable part 3, as described above; the spring 30 and the spring 17 are extended, the sleeve 18 and the electric motor M are retracted into the body 2, and the control shaft 10 is maintained in its retracted position by the spring 17, so that the operating rods 4' and 5' are rotated towards each other, so that the jaws 4 and 5 are closed. The stop pin 14 is located at the lower limit stop in the groove 15 of the rotatable part 3. The spring 17 constantly exerts a thrust that keeps the control rod 10 retracted without stress. As mentioned above, the holder 1 is usually closed, such as Figure 4 shown.

[0120] Figure 5 is an axial cross-sectional view of the clamp 1 shown in an open configuration, which is an alternative to the normally closed configuration and which occurs only upon command and lasts for a predetermined time interval. Due to the pressure exerted by the compressed air, which is supplied by the pipeline 509 through the fitting 31 command, the piston 26 is located at the top dead center pms in the cylinder 28. As a result, the rod 27 of the piston 26 is fully raised and abuts and is coupled to the motor shaft 22 of the electric motor M. The springs 17 and 30 are compressed, and the sleeve 18 is also at the corresponding top dead center pms; in particular, the thrust exerted by the piston 26 through the second kinematic chain including the shafts 27 and 22 overcomes the force constantly exerted by the spring 17 so as to keep the clamp about Figure 4 Thus, the control shaft 10 is pushed by the rod 27 of the piston 26 to be withdrawn from the body 2 and the operating levers 4' and 5' are displaced to Figure 5 , to correspond to the spaced apart jaws 4, 5. The stop pin 14 is located at an upper limit stop in the slot 15 of the rotatable part 3. The gripper can be selectively brought into an open configuration with the jaws 4, 5 spaced apart, thanks to compressed air and the pneumatic actuator 25. The electric motor M is switched off and does not impart rotation to the drive shaft 22.

[0121] In practice, Figure 4 In the configuration shown, the control shaft 10 is thus rotatable but not translatable about the longitudinal axis XX and Figure 5 In the configuration of , the control shaft 10 is translatable but not rotatable on the longitudinal axis XX.

[0122] Figure 6is a perspective view of a gripper 1 and a container V arranged beside the gripper 1. The gripper 1 is in a normally closed configuration, with the jaws 4 and 5 closed together. The electric motor M is switched off and does not draw current. The jaws 4 and 5 are shaped complementary to the contour of the container V.

[0123] Fig. 7A Shows that Figure 4 and Figure 6 The same configuration of the holder 1, i.e. it is in the closed configuration, but the holder 1 is mounted on a circular frame 501. Figure 1 The electric motor M is only shown schematically. The circular frame 501 is stopped at this point in order to allow the container V to be subsequently inserted between the jaws 4, 5 after the jaws 4, 5 have been opened, as will be seen in FIG. Figure 8 As shown in FIG. 2 , the piston 26 is at pmi.

[0124] Figure 7B yes Fig. 7A 1 is an enlarged view of the portion shown in the dotted box, which shows in detail the portion of the clamp 1 in which the rod 27 of the piston 26 and the drive shaft 22 of the electric motor face and remain separated. It can be noted that there is indeed a gap between the end of the rod 27 and the end of the drive shaft 22, and the two shafts do not contact each other.

[0125] Figure 8 is a perspective view of the gripper 1 and a container V inserted between the jaws 4 and 5 but not held. The gripper 1 is in an open configuration, in particular a maximum open configuration, in which the jaws 4 and 5 are at their maximum distance; it can be noted that the jaws 4 and 5 protrude slightly from the guide 6 of the rotatable part 3. An external device pushes the container V between the jaws 4 and 5. Thus, in Figure 8 In the embodiment, there is a gap between the jaws 4, 5 and the container V, which is precisely to allow insertion.

[0126] Fig. 9A Shows that Figure 5 and Figure 8 The same configuration of the holder 1, i.e. it is in the open configuration, but the holder 1 is mounted on the circular frame 501. Figure 1 The electric motor M is only shown schematically. At this time, the container V is inserted between the clamping jaws 4 and 5. Figure 8 Compressed air is supplied to the cylinder 28 and the piston 26 is at pms, so the rod 27 is in the maximum extended position outside the cylinder 28. Observe Fig. 9A In the lower part of the container V, it can be seen that there is a gap between the container V and the open clamping jaws 4, 5. The end 10' of the control rod 10 is almost inserted between the clamping jaws 4 and 5.

[0127] The piston 26 is configured to interact with the control shaft 10 throughout at least a portion of the travel of the piston 26. In particular, the piston 26 may be functionally constrained to the control shaft 10 so as to apply a longitudinal thrust to the control shaft 10 to cause longitudinal translation thereof, as will now be explained.

[0128] Fig. 9B yes Fig. 9A 1 is an enlarged view of the portion shown in the dotted box in the figure, and shows in detail the portion of the clamp 1 in which the rod 27 of the piston 26 and the drive shaft 22 of the electric motor are abutted and coupled. The spring 30 is compressed, and the rod 27 of the piston 26 has indeed pushed the drive shaft 22 and the entire electric motor M to the top dead center inside the body 2. Therefore, the control shaft 10 can be pushed longitudinally by the piston 26 resting thereon.

[0129] Fig.10 is a perspective view of the gripper 1 and a container V inserted and held between the jaws 4 and 5. The gripper 1 is in a closed configuration, in particular in a configuration that is not maximally closed (e.g. Figure 4 , Figure 6 , Fig. 7A and Figure 7B ), but rather in an intermediate position between the previously shown configurations, in which the jaws 4 and 5 are not at the corresponding minimum distance, since there is a container V between them and the jaws 4, 5 must be able to exert pressure to hold it. In this respect, the spring 17 has the function of exerting the force required by the jaws 4 and 5 to then exert sufficient force on the container V to effectively hold the container V during rotation. As indicated by the arrow R, in this configuration, the rotatable part 3 of the gripper 1 rotates together with the container V on the longitudinal axis XX.

[0130] Fig.11A Shows that Fig.10 The configuration of the same configuration of the gripper 1. As can be seen by comparing Fig.11A and Fig. 7A It can be noted that the jaws 4, 5 are not in the same relative position, although the piston 26 is in Fig.10 and Fig.11A This difference is compensated by the spring 17 which, as mentioned above, is preloaded and works in extension; therefore, Fig.11A Spring 17 in Fig. 7A The same spring 17 shown in FIG. 1 is slightly less extended. This feature does ensure that the pressure is continuously applied to the container V by the jaws 4 , 5 .

[0131] Fig. 11B yes Fig.11A1 and 2 show in detail the portion of the gripper 1 in which the rod 27 of the piston 26 and the drive shaft 22 of the electric motor face and remain separated. It can be noted that there is indeed a gap between the end of the rod 27 and the end of the drive shaft 22, and the two shafts do not touch each other. Due to the compensation just explained, Fig. 11B The distance between the axes 22 and 27 is greater than Figure 7B The distance between the same axes 22 and 27 in FIG.

[0132] When the container V has been inspected, the rotation R stops and the gripper 1 can be opened, as shown. Figure 8 As shown, to release container V.

[0133] Fig. 12A is a perspective view of a gripper hand 600 (end of an arm tool) of an industrial manipulator intended to move a cover 32 of a container V and to tighten and loosen the cover 32 on a respective container V. For simplicity, only the gripper 1 ' according to different embodiments of the invention of the gripper hand 600 is shown, without showing the support structure, electrical and pneumatic connections, etc. of the gripper 1 '. It is assumed that the body 2 of the gripper 1 ' is held by the support structure of the gripper hand 600.

[0134] It can be noted that according to the present invention, the gripper hand 600 comprises 25 grippers 1' arranged side by side in a 5×5 matrix configuration. Correspondingly, twenty-five containers V covered with lids 32 are arranged on the tray 33, ready for uncapping. In other words, the gripper hand 600 has the task of unscrewing the lids 32 from the containers V present in the tray 33.

[0135] The holder 1 ′ is oriented vertically, ie the longitudinal axis XX is vertical and the rotatable part 3 faces the tray 33 .

[0136] As can be noted, the grippers 1 ′ are each provided with four jaws 34 arranged in a cross shape on the rotatable part 3 and sliding in corresponding radial guides of the rotatable part 3. Fig. 12A In the embodiment of the present invention, the gripping hand 600 has been immediately brought over the pallet 33 so that the cover 32 is located in the effective radius of the clamping jaws 34 , ie the cover 32 is located between the opened clamping jaws 34 .

[0137] Fig. 12B describes this configuration better. It is Fig. 12A. The four jaws 34 are each provided with a finger 35 extending parallel to the longitudinal axis XX of the gripper 1 '. Each finger 35 is damped and telescopic so that the gripper 1 ' can be lowered until the finger 35 is brought against the container V. Each finger 35 comprises a spring 36 that constantly applies a thrust to keep the finger 35 extended and a rubber end 37 intended to rest on the cover 32, in particular on the outer side surface of the cover 32, and to exert pressure. It can be noted that the end 37 does not contact the cap 32.

[0138] Fig.13A is a perspective view of the same gripper hand 600, wherein the gripper 1' is in a different configuration, in particular wherein the gripper 1' grips a corresponding cap 32. The cap 32 of a container V is unscrewed from the container V and picked up. In fact, Fig.13A The holder 1 ′ is shown with the cover 32 held by the jaws 34 .

[0139] Fig. 13B yes Fig.13A 1 is an enlarged view of a portion enclosed in a dotted frame, and shows the end portion 37 of the clamping cover 32 in more detail.

[0140] The electric actuator of the clamp 1 ′ is used to rotate the rotatable part 3 and achieve tightening or loosening of the cover 32 , and the pneumatic actuator of the clamp 1 ′ is used to achieve opening of the clamping jaws 34 .

[0141] In the embodiment 1', the electric motor M is actually a gear motor, in particular a gear motor with an epicyclic reduction gear.

[0142] In summary, the advantages provided by the clamp 1 are as follows:

[0143] - full interchangeability with respect to the holders 502 of known art used in the inspection device 500 of the containers V, due to the fact that the outer diameter of the body 2 is equal to that of the holder 502;

[0144] - the gripper 1 is equipped with both an electric actuator, which controls the rotation of the rotatable part 3 and the jaws 4, 5, and a pneumatic actuator, which controls the opening of the jaws 4, 5 (considering the gripper 1 to be normally closed), so that the gripper 1 does not require the inspection device 500 to be specially equipped with its own actuators;

[0145] - the electric actuator is a single electric motor;

[0146] - the structure of the holder 1 is relatively simple, since it does not provide concentric shafts (the shafts 22 and 27 are coaxial, but not concentric, and slide one inside the other), which makes it possible to assemble it in a short time and without excessive costs;

[0147] - The gripper 1 allows to exclude belts 506 which are problematic in clean rooms due to the dust they generate as they wear.

[0148] Further advantages of the structure with separate shafts 22 and 27 are:

[0149] - No need to rotate the compressed air distributor on the holder 1;

[0150] - the washer 29 does not rotate in the chamber 28 of the pneumatic piston 26 and is therefore durable;

[0151] - By pushing the rear of the drive shaft 22, the usually smaller bearing inside the motor M itself (which is Figure 4 and Figure 5 (visible but not numbered) will not be stressed by the load of spring 17.

Claims

1. A gripper (1, 1') for an industrial manipulator, comprising: a body (2) having a longitudinal axis (XX), an electric actuator (M), housed in the body (2), a rotatable part (3) constrained to said body (2) and rotatable relative to said body (2) on said longitudinal axis (XX), jaws (4, 5, 34) mounted on the rotatable part (3) and movable towards and away from each other in order to hold and release the workpiece (V), a control shaft (10) engaged with the clamping jaws (4, 5, 34) and coupled to an electric actuator (M), wherein the control shaft (10) can be rotated on a longitudinal axis (XX) by the electric actuator (M) to rotate the rotatable part (3) and the clamping jaws (4, 5, 34), and the control shaft (10) can be translated along the longitudinal axis (XX) to move the clamping jaws (4, 5, 34) closer to or farther away from each other; a pneumatic actuator (26, 28) housed in the body (2), wherein the pneumatic actuator (26, 28) comprises a piston (26) movable between a bottom dead center (PMI) and a top dead center (PMS) in response to pressure applied by compressed air supplied to the gripper (1) by an external device (509), and wherein the piston (26) is configured to exert a thrust on the control shaft (10) during at least a portion of the stroke of the piston (26), and wherein the movement of the piston (26) between the bottom dead center (pmi) and the top dead center (pms) causes the control shaft (10) to translate along the longitudinal axis (XX) and actuate the clamping jaws (4, 5, 34), Features: The electric actuator (M) and the pneumatic actuator (26, 28) are configured to remain separated and not interact with each other when the electric actuator (M) is opened, and The electric actuator (M) and the pneumatic actuator (26, 28) are configured to remain integrated when the pneumatic actuator (26, 28) is activated.

2. The holder (1, 1') according to claim 1, wherein: The electric actuator (M) is an electric motor or a gear motor having a drive shaft (22) rotatable on the longitudinal axis (XX), and the drive shaft (22) rotates integrally with the control shaft (10).

3. The holder (1, 1') according to claim 2, wherein: The control shaft (10) and the drive shaft (22) are non-telescopically butt-coupled.

4. The holder (1, 1') according to any one of the preceding claims, wherein The electric actuator is an electric motor or a gear motor (M) slidably accommodated in the body (2), and the electric motor or the gear motor (M) is easy to translate along the longitudinal axis (XX) between a lower dead center (pmi) and an upper dead center (pms), and wherein the lower dead center of the electric motor or the gear motor (M) corresponds to a reciprocating position of the clamping jaws (4, 5, 34) selected from the closed position and the separated position, and wherein the upper dead center of the electric motor or the gear motor (M) corresponds to another reciprocating position of the clamping jaws (4, 5, 34) selected from the closed position and the separated position.

5. The holder (1, 1') according to claim 4, wherein: It comprises an elastic element (17) functionally interposed between the body (2) and the electric actuator (M) so as to counteract the translation of the electric actuator (M) along the longitudinal axis (XX).

6. The holder (1, 1') according to claim 5, wherein: The elastic element is a spring (17) housed in the body (2) between the rotatable part (3) and the electric actuator (M), and wherein the spring (17) is preloaded and constantly applies a thrust to the electric actuator (M) in a direction causing the electric actuator (M) to reach a corresponding bottom dead center (pmi), the bottom dead center (pmi) corresponding to the jaws (4, 5, 34) being close together.

7. The holder (1, 1') according to claim 6, wherein: The spring (17) is coaxial with the longitudinal axis (XX).

8. The holder (1, 1') according to any one of the preceding claims 5-7, wherein It comprises a sleeve (18) which is constrained to the electric actuator (M) and is concentric with the drive shaft (22) and the control shaft (10) and with the elastic element (17), wherein when the electric actuator (M) is at the corresponding top dead center (pms), the sleeve (18) contacts the end of the body (2) of the clamp (1) to determine the limit stop.

9. The holder (1, 1') according to claim 8, wherein: The sleeve (18) comprises a plurality of radial pins (19) which are inserted through corresponding radial through holes (20) drilled through the side wall of the body (2) of the holder (1), and wherein, for each radial pin (19), the sleeve (18) comprises a slot (21) elongated in the axial direction, and wherein the radial pins (19) each engage the corresponding elongated slot (21), and wherein the axial limit stop of the sleeve (18) corresponds to the radial pin (19) abutting against one of the two ends of the corresponding elongated slot (21).

10. The holder (1, 1') according to any one of the preceding claims, wherein The jaws (4, 5, 34) are slidably received in corresponding guides (6) of the rotatable part (3), and wherein, for each jaw (4, 5, 34), the clamp (1) comprises a rod (4', 5') pivoted to the rotatable part (3) and swinging in a plane parallel to the longitudinal axis (XX), and wherein the end (10') of the control shaft (10) is slidably inserted in the rotatable part (3) and engages the rod (4', 5'), and wherein the angular position of each rod (4', 5') corresponds univocally to the axial position of the control shaft (10).

11. The holder (1, 1') according to any one of the preceding claims, wherein It comprises a pin (14) which is radially inserted through the control shaft (10), wherein the pin (14) engages in a slot (15) of the rotatable part (3) so as to transmit rotation to the longitudinal axis (XX), and wherein the pin (14) is able to slide axially in the slot (15), and wherein the axial length of the slot (15) is greater than or equal to the axial stroke of the control shaft (10), or alternatively, at least a portion of the control shaft (10) has a non-circular cross-section and engages with a corresponding complementary guide member of the rotatable part (3).

12. The holder (1, 1') according to any one of the preceding claims, wherein The end (10') of the control shaft (10) protrudes from the body (2) of the clamp (1) and engages the rotatable part (3), and wherein the control shaft (10) is telescopically movable between a retracted position and an extended position, the retracted position and the extended position corresponding to a state selected from the state in which the clamping jaws (4, 5, 34) are close together and the state in which the clamping jaws (4, 5, 34) are spaced apart.

13. The holder (1, 1') according to any one of the preceding claims, wherein The piston (26) comprises a thrust portion or rod (27), and wherein, at the bottom dead center (pmi) of the piston (26), the rod (27) is separated from the electric actuator (M) and does not apply thrust, and wherein, at the top dead center (pms) of the piston (26), the rod (27) abuts against the electric actuator (M) and applies an axial thrust thereon.

14. The holder (1, 1') according to claim 13, wherein: The electric actuator (M) is an electric motor or a gear motor having a drive shaft (22) that can rotate on the longitudinal axis (XX) and passes through the electric motor (M), and wherein the rod (27) of the piston (26) can abut against the end of the drive shaft (22).

15. The holder (1, 1') according to claim 14, wherein At the bottom dead center (pmi) of the piston (26), the rod (27) is separated from the drive shaft (22) and is rotationally decoupled therefrom.

16. The holder (1, 1') according to any one of the preceding claims 13-15, wherein A preloaded elastic element (30) for counteracting the axial displacement of the piston (26) is included, and the elastic element (30) constantly applies a thrust force on the piston (26) in a direction to move the piston (26) away from the electric actuator (M).

Images